Oscillation-detector.



PATENTED OCT. 8, 1907.

L. DE FOREST. OSGILLATION DETECTOR. APPLICATION FILED Jun: 12. 1907'.

UNIT D sT rns PATENT OFFICE.

* LEE DE FOREST, 0] NEW YORK, N. Y., ASSIGNOR T0 (1 EORGE K. \\'OOl )\\'Olll.ll, OI BOSTON,

NASSAU I SIC'ITS.

OSCILLATION-DETECTOR.

specification of Letters Patent.

Patented Oct. 8, 1907.

Original application filed February 2, 1905, Serial No. 243,913- Divided and this application filed June 12, 1907. Serial No. 378,504.

To all whom it may concern:

Be it known that I, LEE nr: Fonnsr, a citizen of the United States, and a resident of New York, in the county of New York and State of New York, have invented a new and useful Improvement in Oscillation- Detectors, of which the following is a specification.

My invention relates to an improvement in the sensitive member used in systems of wireless telegraphy to detect the electrical waves or oscillations and comprises the novel features hereinafter shown and described and particularly pointed out in the claims.

In the accompanying drawing, I have shown, and-in the description thereof will point out, a certain form of construction and an arrangement of circuit which may be employed in carrying out my invention, and in connection therewith I will point out the principle of my invention. It will be understood, however, that by no means all the known or possible embodiments of my invention are herein illustrated or described and that the particular embodiment herein shown and described may be subjected to a wide range of variation without departing from the principle of my invention.

The drawing represents a space telegraph receiving system having connected therein one embodiment of a the oscillation responsive device which constitutes the subject matter of the present invention. It will be understood, however, that said oscillation responsive device and its local circuit may be connected in any suitable manner with a wireless telegraph receiving system.

In the figure, A represents an antenna or receiving conductor, or wav'e intercepting means; E represents the earth connection, D represents a Bunsen burner; T is a receiving or indicating instrument which is herein shown as a telephone receiver, the same being shown only as typical of any form of signal indicating device capable of being employed.

I have discovered that if two electrodes or conductive members be separated, the separation between them may be neutralized sui'liciently to enable them to act as a detector of electrical oscillations, if the intervening gaseous medium which-separates said electrodes be maintained in a condition of intense molecular and ionic activity, such for instance as would be caused by heating said gaseous medium in any suitable manner. This principle is embodied in the apparatus illustrated in the drawing. Obviously the electrode F which is placed as shown in the flame of the Bunsen burner, is maintained at a high temperature relative to the lip of the burner which is of relatively low temperature. Thus there is formed a local receiving circuit possessing a certain asymmetric electrical conductivity, whereby the current from the battery ll, if used, will flow more readily from the relatively cool burner D to the more highly heated electrode F this local circuit comprising the burner D, telephone or other signal indicating device T, electrode F, that portion of the flame intervening between the electrode 1" and the burner D, and the battcry B, if employed. In this case the burner itself forms one of the two electrodes or conductive members above referred to as separated by a gaseous medium maintained in a condition of intense molecu' lar and ionic activity.

Although I have shown a Bunsen burner for the purpose of maintaining the gaseous medium intervening between the electrodes D and F in a condition of intense molecular activity by the combustion of gases intervening between said electrodes, it will be understood that I do not limit myself to this particular heating device, which is not essential, as any means of heating may be employed.

The influence of the electrical oscillations developed in the oscillation circuit A-E produces current variations in the aforesaid local circuit, thus affecting the indicating instrument therein to produce a signal. This may be due to ionization of the gas intervening between the electrodes, which greatly increases tllO conductivity of said gas, said ionization being accomplished in the present instance by putting said gas into a condition of intense molecular activity.

This application is a division of my application Serial No. 243,913, filed Feb. 2, 1905, and the figure of the drawing accompanying the present application is identical with Fig. 4 of the patent application.

I claim:

1. An oscillation responsive device comprising a Bunsen but-nor. an electrode placed in the flame thereof, a local circuit connecting said burner and electrode, a signal indicating device and a source of electromotive force conncct'ed in said local circuit, and means whereby the oscii lations to be detected may be impressed upon said flame.

2. An oscillation responsive device comprising a gaseous medium maintained in a condition of molecular and ionic activity. two electrodes associated with said gaseous medium, one of said electrodes being maintained at a high temperature and the other at a relatively lower temperature a local circuit connecting said electrodes, a source of electromotivc force and a signal indicating device connected in said local circuit, and means whereby the oscillutious to be detectedmay be impressed upon said gaseous medium 3. An oscillation responsive device comprising'a gaseous medium maintained in a condition of molecular and ionic activity. two electrodes associated with said gaseous medium. one of said electrodes being maintained at a high temperature and the other at :1 relatively lower tempera- Correction in Letters Patent No. 867,878.

eiectromotive force included in said'iocal circuit; a signaL indicating device operatively connected with said local circuit. and means whereby the oscillations to he detected may he impressed upon said gaseous medium.

4. An oscillation responsive device comprising a gaseous medium maintained in a condition of molecular and ionic activity, tun electrodes associated with said gaseous medium. one of said electrodes being maintained at: a high temperature and the other at a relativel v lower tempera ture, means whereby the oscillations to be detected may he impressed upon said gaseous medium, and means operatively connected therewith and responsive to alterations in the conductivity thereof.

5. .\n oscillation responsive device comprising a gaseous medium maintained in a condition ot. molecular and ionic activity. two electrodes associated with said gaseous me- (iilllll. one of said eieclrodes being maintained at: a relatively high temperature with respect to the other, means whereby the electrical oscillations to be detected may he [SEAL] with said local circuit and means whereby the osciila-.

tions to be detected may be impressed upon said gaseous medium.

In testimony whereof, I have hereunto subscribed my name this l-ith day of Mayilfi07t LEE DE FOREST.

Witness s:

'InouAs l. GALLAGHER, lloscos KENT.

It; is hereby certified that'in Letters Patent No. 867,878, granted Octoher 8, 1907, upon the application of Lee de Forest, of New York, N. Y., for an improvement in Oscillation-Detectors, an error appears in the printed specification requiring cor-- rection, as follows In line 85, page 1, the word patent/"should read parent; and that the said Letters Patent-should be read with this correction the'reinthat the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 29th day of October, A. D 1907.

E. B. MOORE,

Commissioner of Patents. 

